Abstract
To understand the formation and growth mechanism of the magnetite phase during the fluidized reduction of hematite, a high-purity hematite ore was isothermally reduced using a 20vol% CO?80vol% CO2 gas mixture in a micro-fluidized bed to examine the process of the selective conversion of hematite to magnetite. The micro-structural characteristics of the magnetite phase were investigated using scanning electron microscopy (SEM) and the Brunauer, Emmett, and Teller (BET) method, and the thickness of the magnetite layer was measured and evaluated using statistical analysis. The experimental results showed that the fresh magnetite nuclei were dense needles of different lengths, and the original hematite grains became porous after complete reduction to the magnetite phase. The thickness of the magnetite layer increased with an increase in reduction temperature and reduction time. The growth kinetics of the magnetite layer was investigated, and the value of the activation energy E was estimated to be 28.33 kJ/mol.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Y.S. Sun, Y.X. Han, P. Gao, and J.W. Yu, Size distribution behavior of metallic iron particles in coal-based reduction products of an oolitic iron ore, Miner. Process. Extr. Metall. Rev., 36(2015), No. 4, p. 249.
J.W. Yu, Y.X. Han, Y.J. Li, P. Gao, and Y.S. Sun, Separation and recovery of iron from a low-grade carbonate-bearing iron ore using magnetizing roasting followed by magnetic separation, Sep. Sci. Technol., 52(2017), No. 10, p. 1768.
T.J. Chun, D.Q. Zhu, and J. Pan, Simultaneously roasting and magnetic separation to treat low grade siderite and hematite ores, Miner. Process. Extr. Metall. Rev., 36(2015), No. 4, p. 223.
L.Q. Luo, M. Chen, H.T. Yan, S.S. Cui, and Y.J. Zhang, Magnetic reduction roasting and magnetic separation of oolitic iron ore, Chin. J. Proc. Eng., 14(2014), No. 4, p. 593.
X.M. Luo, Y.F. Wang, S.M. Wen, M.Z. Ma, C.Y. Sun, W.Z. Yin, and Y.Q. Ma, Effect of carbonate minerals on quartz flotation behavior under conditions of reverse anionic flotation of iron ores, Int. J. Miner. Process., 152(2016), p. 1.
D. Li, W.Z. Yin, J.W. Xue, J. Yao, Y.F. Fu, and Q. Liu, Solution chemistry of carbonate minerals and its effects on the flotation of hematite with sodium oleate, Int. J. Miner. Metall. Mater., 24(2017), No. 7, p. 736.
X.M. Luo, W.Z. Yin, Y.F. Wang, C.Y. Sun, Y.Q. Ma, and J. Liu, Effect and mechanism of siderite on reverse anionic flotation of quartz from hematite, J. Cent. South Univ., 23(2016), No. 1, p. 52.
X.M. Luo, W.Z. Yin, Y.F. Wang, C.Y. Sun, Y.Q. Ma, and J. Liu, Effect and mechanism of dolomite with different size fractions on hematite flotation using sodium oleate as collector, J. Cent. South Univ., 23(2016), No. 3, p. 529.
S. Song, S. Lu, and A. Lopez Valdivieso, Magnetic separation of hematite and limonite fines as hydrophobic flocs from iron ores, Miner. Eng., 15(2002), No. 6, p. 415.
L.Q. Luo, J.S. Zhang, and Y.F. Yu, Recovering limonite from Australia iron ores by flocculation-high intensity magnetic separation, J. Cent. South Univ. Technol., 12(2005), No. 6, p. 682.
Q.S. Zhu and H.Z. Li, Status quo and development prospect of magnetizing roasting via fluidized bed for low grade iron ore, CIESC J., 65(2014), No. 7, p. 2437.
J.W. Yu, Y.X. Han, Y.J. Li, and P. Gao, Beneficiation of an iron ore fines by magnetization roasting and magnetic separation, Int. J. Miner. Process., 168(2017), p. 102.
X. Liu, Y. Yu, Z. Hong, Z. Peng, J. Li, Q. Zhao, Development and application of packaged technology for flash (fluidization) magnetizing roasting of refractory weakly magnetic iron ore, Min. Metall. Eng., 37(2017), No. 2, p. 40.
W. Chen, Y.F. Yu, Z. Feng, X. Lu, Q. Zhao, X. Liu, Six hundred thousand t/a refractory siderite flash magnetizing roasting complete sets technique and equipment, Met. Mine, 2017, No. 3, p. 54.
Y.F. Yu and W. Chen, Application of flash magnetizing roasting technique in beneficiation of siderite and limonite, [in] International Symposium on Project Management, Shuyang, 2010, p. 13.
A. Boehm, M. Boehm, and A. Kogelbauer, Neutrons for mineral processingthermo diffractometry to investigate mineral selective magnetizing flash roasting, Chem. Ing. Tech., 86(2014), No. 6, p. 883.
Y. Li and T. Zhu, Recovery of low grade haematite via fluidised bed magnetising roasting: investigation of magnetic properties and liberation characteristics, Ironmaking Steel-making, 39(2012), No. 2, p. 112.
Y.J. Li, R. Wang, Y.X. Han, and X.C. Wei, Phase transformation in suspension roasting of oolitic hematite ore, J. Cent. South Univ., 22(2015), No. 12, p. 4560.
Y.F. Yu and C.Y. Qi, Magnetizing roasting mechanism and effective ore dressing process for oolitic hematite ore, J. Wuhan. Univ. Technol., 26(2011), No. 2, p. 176.
C. Feilmayr, A. Thurnhofer, F. Winter, H. Mali, and J. Schenk, Reduction behavior of hematite to magnetite under fluidized bed conditions, ISIJ Int., 44(2004), No. 7, p. 1125.
J.W. Yu, Y.X. Han, Y.J. Li, and P. Gao, Recovery and separation of iron from iron ore using innovative fluidized magnetization roasting and magnetic separation, J. Min. Metall. B, 54(2018), No. 1, p. 21.
J.W. Yu, Y.X. Han, P. Gao, Y.J. Li, S. Yuan, and W.B. Li, An innovative methodology for recycling iron from magnetic preconcentrate of an iron ore tailing, Physicochem. Prob. Miner. Process., 54(2018), p. 668.
J.W. Yu, Y.X. Han, Y.J. Li, P. Gao, and W.B. Li, Mechanism and kinetics of the reduction of hematite to magnetite with CO-CO2 in a micro-fluidized bed, Minerals, 7(2017), No. 11, 209.
J.W. Yu, Y.X. Han, Y.J. Li, and P. Gao, Recent advances in magnetization roasting of refractory iron ores: A technological review in the past decade, Miner. Process. Extr. Metall. Rev., 2019. DOI: 10.1080/08827508.2019.1634565
Y.S. Sun, X.R. Zhu, Y.X. Han, and Y.J. Li, Green magnetization roasting technology for refractory iron ore using side-rite as a reductant, J. Cleaner Prod., 206(2019), p. 40.
X.L. Zhang, Y.X. Han, Y.S. Sun, and Y.J. Li, Innovative utilization of refractory iron ore via suspension magnetization roasting: A pilot-scale study, Powder Technol., 352(2019), p. 16.
X.L. Zhang, Y.X. Han, Y.S. Sun, Y. Lv, Y.J. Li, and Z.D. Tang, An novel method for iron recovery from iron ore tailings with pre-concentration followed by magnetization roasting and magnetic separation, Miner. Process. Extr. Metall. Rev., 2019. DOI: 10.1080/08827508.2019.1604522
G.W. Yang, X.J. Sun, Q.L. Yong, Z.D. Li, and X.X. Li, Austenite grain refinement and isothermal growth behavior in a low carbon vanadium microalloyed steel, J. Iron Steel Res. Int., 21(2014), No. 8, p. 757.
Y.S. Sun, Y.X. Han, Y.J. Li, and Y.F. Li, Formation and characterization of metallic iron grains in coal-based reduction of oolitic iron ore, Int. J. Miner. Metall. Mater., 24(2017), No. 2, p. 123.
M. Et-Tabirou, B. Dupré, and C. Gleitzer, Hematite single crystal reduction into magnetite with CO-CO2, Metall. Trans. B, 19(1988), No. 2, p. 311.
Acknowledgements
This work was financially supported by the National Science Foundation of China (Nos. 51734005 and 51674065), the China Postdoctoral Science Foundation (No. 2018M631812), and Open Foundation of State Key Laboratory of Mineral Processing, Beijing General Research Institute of Mining & Metallurgy Group, China (No. BGRIMM-KJSKL-2019-09).
Author information
Authors and Affiliations
Corresponding authors
Rights and permissions
About this article
Cite this article
Yu, Jw., Han, Yx., Li, Yj. et al. Growth behavior of the magnetite phase in the reduction of hematite via a fluidized bed. Int J Miner Metall Mater 26, 1231–1238 (2019). https://doi.org/10.1007/s12613-019-1868-8
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12613-019-1868-8